/**
 * #      988
 * 名称   从叶结点开始的最小字符串
 * 链接   https://leetcode-cn.com/problems/smallest-string-starting-from-leaf
 * 题解   [77](https://leetcode-cn.com/problems/smallest-string-starting-from-leaf/solution)
 * 通过率 48.0%
 * 难道   中等
 */

